The present invention relates generally to automated fuel cell fabrication and, more particularly, to an apparatus and method for converting a web of a fuel cell membrane to separate membrane sheets and accurately positioning the separated membrane sheets for subsequent processing.
Various apparatuses have been developed to convert a web of a given material to individual sheets. Converting extremely thin web structures on the order of a thousandth of an inch thick renders conventional converting processes generally unworkable for such applications. One particular structure of interest in the construction of fuel cells is the thin membrane of the fuel cell. An apparatus for converting a membrane web must be capable of handling and cutting very thin, two-sided membrane structures of the web and, once cut, properly aligning the membrane sheets for downstream processing. Disrupting the positioning of the membrane sheets at a particular process station can result in damage to the membrane sheets or the fuel cell structures that incorporate such membrane sheets. Disturbing membrane sheet orientation is also likely to result in reduced product throughput, which negatively affects the productivity of the automated fuel cell assembly line.
It is often desirable to automate, either partially or completely, a number of web converting processes. Many conventional web converting apparatuses and methods are not well suited for a high degree of automation, particularly converting processes which have tight positional tolerance requirements.
There is a need for improved web converting apparatuses and methodologies. There is a further need for such apparatuses and methodologies that can safely and precisely convert a web of very thin web structures to individual sheets in an automated assembly environment, such as in an automated fuel cell assembly plant. The present invention fulfills these and other needs.
The present invention is directed to an apparatus and method for automatically converting a web of a thin patterned catalyst-coated membrane to separate membrane sheets for fuel cell assembly. A first side of the membrane web is coated with an anode catalyst and a second side of the membrane web is coated with a cathode catalyst. The membrane is typically less than about two thousandths of an inch in thickness, and typically has a thickness of about one thousandths of an inch.
An automated web converting method involves transporting, with use of a movable vacuum, an end portion of the membrane web from a first location to a second location. With use of respective first and second vacuums at the first and second locations, and after removal of the movable vacuum, the end portion of the membrane web is releasably secured at the first and second locations. The membrane web is cut within a gap defined between a single catalyst pattern of the membrane web end portion and an adjacent catalyst pattern to produce a membrane sheet. The membrane sheet is precisely positioned to a desired orientation to facilitate subsequent processing of the membrane sheet.
An apparatus for automatically converting a web of a thin patterned catalyst-coated membrane to separate membrane sheets for fuel cell assembly includes a staging station comprising a first vacuum and a gap detector. The gap detector detects a gap between catalyst patterns of the membrane web. The staging station receives the end portion of the membrane web. A positioning station includes a positioning table and a second vacuum. The positioning table is controllable to move axially and rotationally. A vision system is provided at the positioning station. The vision system detects an orientation of a membrane sheet cut from the membrane web with use of a cutter. A robot, comprising a vacuum chuck, is moveable between at least the staging station and the positioning station.
A controller is programmed to cause the robot to transport, with use of a vacuum at the vacuum chuck, the end portion of the membrane web from the staging station to the positioning table, to selectively actuate and deactivate the first and second vacuums and the vacuum chuck vacuum when causing the cutter to cut the membrane web within the gap between catalyst patterns, and to control movement of the positioning table so that the membrane sheet is moved to a desired orientation to facilitate subsequent processing of the membrane sheet.
The above summary of the present invention is not intended to describe each embodiment or every implementation of the present invention. Advantages and attainments, together with a more complete understanding of the invention, will become apparent and appreciated by referring to the following detailed description and claims taken in conjunction with the accompanying drawings.